Flashproof fuse plugs



Sept. 16, 1958 G. w. VALENTINE 2,852,641

FLAsHPRooF FUSE PLUGS Filed Dec. 9, 1955 INVENTO gow/anya en lne.

United States Patent FLASHPROOF FUSE PLUGS Garden W. ValentineyOwosso,Mich. Application December 9, 1955,Serial1No. 552,107 3 Claims. (Cl.20d-130) Thisinvention relates to electrical :plug fuses such as used inelectric circuits to 'form a safety link and open the circuit when toomuch current is flowing through the line, a short circuit occurs, orthere is a sudden rush or surge of current of dangerous proportions.

The principal object of the invention is to design a sealed-in ashproofplug fuse which smothers any flash or explosion caused by a shortcircuit, poor contact, or surge or overload of current of dangerousproportions in the circuit.

Another object of the invention is to provide a very simple, practical,and inexpensive sealed-in ashproof plug fuse which can be readilymanufactured and assembled, and which in general appearance issubstantially the same as the plug fuse at present on the market.

Still `a further object is to design a llashproof plug fuse in which the'fuse element is embedded in an insulating material eliminating accidenthazards, by smothering any liash or spark which might produce a firewhen there is a poor connection, the plug fuse loosely mounted and/ oroverloaded.

A furtherobject still is to provide a flashproof plug fuse provided witha sealed-in insulating material in which the fuse element is embedded,making up a fuse which is economical to manufacture, and which fits alltypes and sizes of plug fuse holders and receptacles at L present on themarket.

Still a further object is to design a ashproof plug fuse in which theinsulating shot or material is sealed in, thus eliminating anypossibility of moisture entering the fuse body or insulation material,and also preventing the escape of sparks or tire when the fuse is blown.

With the above and other Aobjects in view, the present inventionconsists in the combination and Varrangement of parts, hereinafter morefully described, illustrated in the accompanying drawing, and moreparticularly pointed. out in the appending claims, it being understoodthat changes may lbe made in the form, size, proportion, and minordetails of construction, without departing from the spirit, orsacrificing any of the advantages of the invention.

ln the drawing:

Fig. l is a side elevational view of my new fiashproof plug fuse.

Fig. 2 is a top plan view thereof.

`- Fig. 3 is `a vertical, transverse sectional view.

Fig. 4 is a perspective view of the fuse element. Fig. 5 is a verticalsectional view of a buss glass tube fuse.

Fig. 6 is a transverse sectional view taken on the line 6-6 of Fig. 5.

Referring now more specifically to Figs. 1-4 inclusive of the drawing,wherein I have shown a plug fuse P of conventional size and shape. Thiscomprises a plug body 8 shaped as clearly shown in Figs. l, 2 and 3 ofthe drawing, and this can be formed of glass, porcelain, or any othersuitable material. The upper end of the plug is enlarged `as at 9, andthe end wall 10 is closed Zzlll Patented Sept. 16, 1958 2 and of reducedthickness as at 11 so that the fuse element may be visible therethrough.

The lower end of the plug 1s shouldered as at 12 to form a cylindricalsection of reduced diameter, and a threaded shell or thimble 14 ismounted on said shoulrock wool, vor any other suitable reproof materialmay be utilized.

A preferably plastic close fitting washer W is inserted in the body 8 atthe point shown and is sealed by means of a liquid plasticizer (notshown), to prevent moisture, gas, etc., entering the material M and alsopreventing escape of sparks when the fuse blows.

The section 15 of fuse element F is disposed relatively close to theinner face of tbe upper end of the receptacle body and is generallycovered by said insulated material, `and the legs 16 and 17 projectdownwardly from section 15 and are embedded in the porcelain 18 whichforms a closure for the lower open end of the plug body, the one leg 16being bent over the lower open end of the body, and thence upwardlybetween the thimble and the body to form a contact with the thimble orshell. The opposite lleg 17 of said fuse element leads downwardly and isconnected to the centrally disposed contact 19 as usual.

The upper end of the fuse or fuse element can be painted or colored witha distinctive color to indicate the fuse amperage or capacity making itunnecessary to read the figures as is presently necessary. For example,the color green could indicate a plug of l5 amperes. The color bluecould indicate a plug of 20 amperes. The color yellow could indicate aplug of amperes, and the color red could indicate a plug of amperes, andso on, so that in a relatively short time the public would be referringto plug fuses by color instead of specifying the amperage, and thiswould be extremely convenient and advantageous inasmuch as the plugs arefrequently replaced in dark areas and places where it is difficult toread the printed indicia on the plugs.

On short circuit or overload of the plug fuse the re duced fuse section15 will blow, but no flame or spark can contact combustible material asthe flash or spark is sealed in and smothered in the fireproof material.

In Figs. 5 and 6 of the drawing I have shown a tubularfuse B with aglass tube body 20 having metallic end caps 21 forming a closure for theopen ends thereof. The fuse element 22. extends from end to end of thetube and is connected to the caps, said element having a reduced section23 as usual. In practice the tube 20 is filled with Ian insulatingmaterial M which surrounds the fuse element, and it will be obvious thatinasmuch as the lireproof material is sealed in any flash will besmothered by said material thus eliminatinfy any possibility of fire orfire hazard. The flashproof material is of a granular nature so any gasformed by the blowing is readily absorbed and no abnormal pressures arebuilt up within the plug body.

From the foregoing description it will .be obvious that I have perfectedla very simple, practical and substantial flashproof plug fuse for usein electrical current circuits of all kinds.

What I claim is:

l. An electrical fuse plug comprising a body member formed of insulatingmaterial and having a chamber therein closed at one end by a transparentwall; a fuse element located in said chamber and having a portion of itslength in 'face to face engagement with said transparent wall so as tobe visible therethrough, the ends of said fuse element leading out ofsaid chamber for connection to electrically conductive parts; aninsulating member closing the other end of said chamber and havingopenings accommodating and closely fitting the ends of said fuse elementso as to seal said chamber; and a quantity of granulated insulatingmaterial filling rsaid chamber and surrounding said fuse element exceptfor said portion in face to face engagement with said transparent Wall,said insulating material being in engagement with the face of saidportion of said fuse element which is opposed to the face :of the latterwhich is in engagement with said transparent Wall.

2. The construction set forth in claim l wherein said portion of saidfuse element is colored to indicate a selected capacity.

3. The construction set forth in claim l, in which the insulatingmaterial is formed of rock Wool shot sealed in said chamber.

References Cited in the tile of this patent UNITED STATES PATENTS Re.19,097 Ringwald Feb. 27, 1934 1,167,964 Young Jan. 11, 1916 1,215,999Schweitzer Feb. 13,V 1917 1,265,223 Marcus May 7, 1918 1,444,637 NuttFeb. 6, 1,923 1,798,169 Riesman Mar. 3l, 1931 2,073,150 Ludwig Mar. 9,1937 FOREIGN PATENTS 10,433 Denmark Ian. l0,

